As a light guide plate used to be built in a large screen television set among light guide plates producing an area light source using LED light, a structure of a light guide plate conventionally has been known in including reflection dots having a cross section in an reverse wedge shape that becomes wider as goes in a proceeding direction of light flux emitted from the light source. See, e.g., Patent Document #1.
Patent Document #1: Japanese Patent Application Publication No. 2008-305713